Golf Club Head With High-Density Heel And Toe Weight And Method Of Making Same

ABSTRACT

A method of forming a golf club head includes providing a body having an end portion (e.g., a heel end or a toe end of the club head) wherein the body end portion includes a lower surface and a boss extending therefrom. The method comprises providing a weight having a top surface and a cavity configured to receive the boss, and inserting the boss on the body into the cavity in the weight by rotating the weight such that the boss interlocks with the cavity and so that at least a portion of the top surface of the weight contacts at least a portion of the lower surface of the body end portion. The weight further includes a protrusion having a concave surface and the body has a corresponding convex surface. The weight is rotated about an axis extending through the body such that the concave surface of the weight bears on the convex surface of the body.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 11/070,308, filed Mar. 1, 2005.

BACKGROUND OF THE INVENTION

This invention relates generally to golf clubs and, in particular, to amethod for fabricating a golf club head having heel and toe weights.

It is often desirable to incorporate heel and toe weighting into a clubhead body to increase the moment of inertia of the club. This increasedmoment of inertia tends to decrease club head twisting in the event thegolfer strikes the golf ball off-center. In an effort to increase themoment of inertia, some prior art club heads utilize a low-densitymaterial for the club head body in conjunction with a higher densitymaterial for the heel and toe weights.

The use of perimeter weighting can lead to a number of manufacturingproblems, however. For example, it is often difficult to join theperimeter weights to the club head body such that the weights aresecurely attached to the body.

Furthermore, in cases where variable or customization of weighting isdesired, known perimeter weighting techniques make it difficult orimpossible to change weighting schemes. This is particularly the casewhere the perimeter weights and club head body are fabricated usingdifferent materials which may not be amenable to the same processingtechniques and whose different mechanical characteristics make themdifficult to join in a robust manner.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective overview of an end portion of a golf club headincluding a body that is interlocked with a weight;

FIG. 2A is a rear elevational view of the club head end portion shown inFIG. 1 before interlocking the body and the weight;

FIG. 2B is anointer rear elevational view of the club head end portionshown in FIG. 1 with the body and the weight partially interlocked; and

FIG. 2C is a further rear elevational view of the club head end portionshown in FIG. 1 with the body and the weight fully interlocked.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention provides a golf club head having a body fittedwith heel and/or toe weights attached in an advantageous manner. Inaccordance with one embodiment of the present invention, a method offorming a golf club head includes providing a body having an end portion(e.g., a heel or a toe end of the club head) wherein the body endportion includes a lower surface and a boss extending therefrom. Themethod comprises providing a weight having a top surface and a cavityconfigured to receive the boss and inserting the boss on the body intothe cavity in the weight by rotating the weight such that the bossinterlocks with the cavity and so that at least a portion of the topsurface of the weight contacts at least a portion of the lower surfaceof the body end portion.

In accordance with one embodiment, the weight further includes aprotrusion having a concave surface and the body has a correspondingconvex surface. The weight is rotated about an axis extending throughthe body such that the concave surface of the weight bears on the convexsurface of the body.

FIG. 1 illustrates an end portion (e.g., a heel end or a toe end) of agolf club head 100, preferably a putter head, including an interlockingbody 102 and a weight 104 in accordance with one embodiment of thepresent invention. As shown, body 102 includes a boss 106 generallyconfigured to interlock with a corresponding cavity 108 within weight(or “ballast”) 104. More particularly, boss 106 includes two generallyarcuate surfaces 110 and 112 which mate with corresponding arcuatesurfaces 120 and 122 within cavity 108 of weight 104, while twogenerally planar surfaces 116 and 114 on opposite sides of boss 106 matewith corresponding planar surfaces 126 and 124 of cavity 108. Hence, itis preferred that the radius of curvature of surfaces 110, 112, 108, and122 are substantially identical (and their centers of rotationcoincident) to facilitate the rotation of weight 104 as boss 106 seatswithin cavity 108. As is known in the art, an exemplary golf putter clubhead typically includes a body having a front (“striking”) face, abottom surface or “sole,” a heel region, and an opposite toe region. Thebody 102 is typically attached to a shaft (not shown) via a suitablehosel (not shown).

FIGS. 2A-2C progressively show the insertion of boss 106 within cavity108 during fabrication of an exemplary putter head. Initially, as shownin FIGS. 1 and 2A, weight 104 is separate from body 102. Weight 104preferably includes an end protrusion 130 having a concave surface 204which is generally configured to rotate about and contact a convexbearing surface 202 on body 102. Body 102 includes a bottom surface 212and weight 104 includes a top surface 210. Boss 106 extends outward frombottom surface 212 of body 102.

As shown in FIG. 2B, weight 104 is positioned such that boss 106 isaligned with and is poised to enter cavity 108, while concave surface204 is placed in contact with convex surface 202 of body 102. Thus,surface 202 provides a point of leverage that assists with rotation ofweight 104 into engagement with boss 106. Weight 104 is then furtherrotated about an axis 205 extending through body 102, which alsogenerally corresponds to the center of curvature of the mating arcuatesurfaces of weight 104 and body 102 (e.g., surfaces 110, 112, 120, and122 shown in FIG. 1). Weight 104 is rotated until it suitably interlockswith body 102, e.g., until surface 210 of weight 104 at least partiallycontacts surface 212 of body 102.

In this regard, weight 104 may be secured to body 104 in any convenientfashion. In the illustrated embodiment, for example, weight 104 issecured using a machine screw 250. Any other suitable method may beused, however, including various adhesives, rivets, pins, interferencefit, soldering, brazing, and/or the like.

In the illustrated embodiment, weight 104 constitutes a portion of oneor more active surfaces of the assembled club head. For example,referring to FIGS. 1, 2A-2C, club head body 102 will typically include afront surface 142. Weight 104 then preferably includes a correspondingfront surface 140 which, in the assembled state, is preferably flushwith the front surface 142 of body 102 thereby forming a striking faceon the club head. Similarly, referring to FIG. 2C, a bottom surface 260of weight 104 may be configured such that it forms a portion of the sole262 of club head body 102.

Body 102 and weight (or weights) 104 comprise any suitable metal,plastic, composite material, or combination thereof. In accordance withone embodiment, body 102 comprises a material such as titanium or ahigh-purity titanium alloy, e.g., commercial pure grade 2 titanium, andweight 104 comprises a material whose density is greater than that ofbody 102—e.g., tungsten. While body 102 and weight 104 may be fabricatedfrom a metallic material, the present invention is not so limited. Forexample, the primary constituent of body 102 might include a compositeor plastic material having the desired characteristics.

Depending upon the selected material or materials, body 102 may befabricated using any suitable process now known or later developed,including a variety of conventional casting methods such asinvestment-casting, powdered-metal processing, and/or metal machining.In one embodiment, body 102 is formed via a suitable casting process andthe assembled unit (with heel and toe weights) is thereafter milled tofinish the various exposed surfaces.

The shape and materials used for body 102 and weight 104 is defined byany suitable factors, including, for example, club head type, desiredmoment of inertia (e.g., the polar moment of inertia around an axisnormal to the club head sole), desired center of gravity, desiredaesthetic properties (e.g., visual cues provided by the club head'scontours as viewed from above during play), and/or the desired weight,mass, and density. In this regard, it will be appreciated that theexemplary club head shapes depicted in FIGS. 1 and 2 are forillustrative purposes only, and that the present invention is not solimited.

It will be appreciated that two weights 104 of equal mass having adensity greater than that of the body 102 may be used in both the heeland toe ends of the club head. This weight placement, toward theantipodal extremes of the toe and heel ends, increases the moment ofinertia of the club head while at the same time keeping the weight lowand close to bottom surface 262 (thus lowering the center of mass andfacilitating desirable spin characteristics upon impact).

The particular shape of boss 106 and cavity 108 as illustrated are notmeant to limit the scope of the present invention. For example, whileboss 106 is shown as a type of solid-of-revolution based on a square orrectangular cross-section, boss 106 may have any suitable shape andcross-section (e.g., circular, oval, curvilinear, rectilinear, or acombination thereof). Boss 106 may also be tapered or have anothersuitably varying cross-section.

Boss 106 may terminate within weight 104 (e.g., at approximately half ofthe thickness of weight 104, as shown in FIG. 2C), or may extendentirely through weight 104 such that it forms a part of sole 262 ofbody 102.

Although the invention has been described herein in conjunction with theappended drawings, those skilled in the art will appreciate that thescope of the invention is not so limited. For example, while the presentinvention has been described in terms of golf putters, many other typesof golf clubs would profit from the present invention, including irons,metal woods, etc. Moreover, while titanium and tungsten have been citedas preferred materials for the body and inserts respectively, it will beappreciated that any suitable material now known or later developed maybe used in connection with the present invention, including variousmetals, alloys, composites, ceramics, and the like. These and othermodifications in the selection, design, and arrangement of the variouscomponents and steps discussed herein may be made without departing fromthe scope of the invention as set forth in the appended claims.

1. A method of forming a golf club head, the method comprising:providing a body comprising a front surface, a rear surface, a bodysurface between the front and rear surfaces, and a first end portionbetween the front and rear surfaces, wherein the first end portioncomprises a lower surface and a boss extending therefrom; providing aweight extending from the front surface of the body to the rear surfaceof the body, the weight comprising a top surface, a cavity to receivethe boss, and a protrusion comprising a weight surface; and interlockingthe boss and the cavity so that at least a portion of the top surface ofthe weight is proximate to at least a portion of the lower surface ofthe first end portion and so that the weight surface induces a forceupon the body surface when the golf club head is at an address position.2. The method of claim 1, further comprising securing the weight to thefirst end portion.
 3. The method of claim 2, wherein: securing theweight to the first end portion comprises fastening the weight to thebody using a screw inserted through the weight into the boss.
 4. Themethod of claim 1, wherein the first end portion of the body correspondsto a heel end of the body.
 5. The method of claim 1, wherein the firstend portion of the body corresponds to a toe end of the body.
 6. Themethod of claim 1, wherein: the body comprises a second end portion; andthe method further comprises providing a second weight to interlock withthe second end portion of the body.
 7. The method of claim 1, wherein:the weight comprises a front surface; and interlocking the boss and thecavity comprises positioning the weight such that the front surface ofthe weight is substantially flush with the front surface of the bodythereby forming a striking face of the golf club head at the frontsurface of the body.
 8. The method of claim 1, wherein: the body furthercomprises a sole; the weight further comprises a bottom surface; andinterlocking the boss and the cavity comprises positioning the weightsuch that the bottom surface of the weight is substantially flush withthe sole.
 9. The method of claim 1, wherein interlocking the boss andthe cavity further comprises: rotating the weight about an axis normalto the front surface of the body so that at least the portion of the topsurface of the weight is proximate to at least the portion of the lowersurface of the first end portion and so that the weight surface inducesthe force upon the body surface when the golf club head is at theaddress position.
 10. The method of claim 1, further comprising:providing a second weight; removing the weight from the body; andinterlocking the body and the second weight.
 11. The method of claim 10wherein: providing the second weight extending from the front surface ofthe body to the rear surface of the body, the second weight comprising asecond weight top surface, a second weight cavity to receive the boss,and a second weight protrusion comprising a second weight surface; andinterlocking the boss and the second weight cavity so that at least aportion of the second weight top surface is proximate to at least theportion of the lower surface of the first end portion and so that thesecond weight surface induces a force upon the body surface when thegolf club head is at the address position.
 12. The method of claim 1,wherein the body surface comprises a convex shape and the weight surfacecomprises a concave shape to mate with the convex shape of the bodysurface.
 13. A club head comprising: a body comprising a front surface,a rear surface, a body surface between the front and rear surfaces, anda first end portion between the front and rear surfaces, wherein thefirst end portion comprises a lower surface and a boss extendingtherefrom; and a weight extending from the front surface of the body tothe rear surface of the body, the weight comprising a top surface, acavity to receive the boss, and a protrusion comprising a weightsurface; wherein: the boss and the cavity interlock so that at least aportion of the top surface of the weight is proximate to at least aportion of the lower surface of the first end portion and so that theweight surface induces a force upon the body surface when the golf clubhead is at an address position.
 14. The club head of claim 13, whereinthe weight is secured to the first end portion.
 15. The club head ofclaim 14, wherein: the weight secured to the first end portion comprisesthe weight fastened to the body using a screw inserted through theweight into the boss.
 16. The club head of claim 13, wherein the firstend portion of the body corresponds to a heel end of the body.
 17. Theclub head of claim 13, wherein the first end portion of the bodycorresponds to a toe end of the body.
 18. The club head of claim 13,wherein: the body further comprises a second end portion; and the clubhead further comprises a second weight that interlocks with the secondend portion of the body.
 19. The club head of claim 13, wherein: theweight further comprises a front surface; and wherein when the boss andthe cavity are interlocked, a front surface of the weight issubstantially flush with the front surface of the body thereby forming astriking face of the golf club head at the front surface of the body.20. The club head of claim 13, wherein: the body further comprises asole; the weight further comprises a bottom surface; and when the bossand the cavity are interlocked, a bottom surface of the weight issubstantially flush with the sole.
 21. The club head of claim 13,further comprising: a second weight having a different density than theweight; wherein: the body interlocks with the second weight.
 22. Theclub head of claim 21 wherein: the second weight extends from the frontsurface of the body to the rear surface of the body, the second weightcomprising a second weight top surface, a second weight cavity toreceive the boss, and a second weight protrusion comprising a secondweight surface; and the boss and the second weight cavity interlock sothat at least a portion of the second weight top surface is proximate toat least the portion of the lower surface of the first end portion sothat the second weight surface induces a force upon the body surfacewhen the golf club head is at the address position.
 23. The club head ofclaim 13, wherein the body surface comprises a convex shape and theweight surface comprises a concave shape to mate with the convex shapeof the body surface.
 24. The club head of claim 13, wherein the bodycomprises a material comprising a density less than a density of theweight.
 25. The club head of claim 24, wherein the body comprisestitanium and the weight comprises tungsten.
 26. The club head of claim13, wherein the club head is a putter head.
 27. The club head of claim13, wherein: the first end portion of the body corresponds to a heel endof the body; the body further comprises a second end portion between thefront and rear surfaces and corresponding to a toe end of the body; andthe club head further comprises a second weight located at the toe endof the body at the front surface and the rear surface.
 28. The club headof claim 27, wherein the weight and the second weight are absent from aportion of the body between the heel end and the toe end.
 29. The clubhead of claim 28, wherein the weight and the second weight extend fromthe front surface of the body to the rear surface of the body.
 30. Theclub head of claim 13, wherein the weight and a second weight extendfrom the front surface to the rear surface.
 31. The club head of claim13, wherein: the body further comprises a top surface; and the weightforms a portion of the top surface.
 32. The club head of claim 13,wherein the boss is integral with the body.
 33. The club head of claim13, wherein: the cavity comprises a shape; and the boss comprises ashape complementary to the shape of the cavity.
 34. A golf clubcomprising: a body comprising a front surface, a rear surface, a bodysurface between the front and rear surfaces, and a first end portionbetween the front and rear surfaces, wherein the first end portioncomprises a lower surface and a boss extending therefrom; a weightextending from the front surface of the body to the rear surface of thebody, the weight comprising a top surface, a cavity to receive the boss,and a protrusion comprising a weight surface; and a golf club shaftcoupled to the body; wherein: the boss and the cavity interlock so thatat least a portion of the top surface of the weight is proximate to atleast a portion of the lower surface of the first end portion and sothat the weight surface induces a force upon the body surface when thegolf club head is at an address position.
 35. The golf club of claim 34wherein: the body surface comprises a convex shape and the weightsurface comprises a concave shape to mate with the convex shape of thebody surface; the end portion of the body corresponds to a heel end ofthe body; the body further comprises a second end portion extendingbetween the front and rear surfaces of the body, and corresponding to atoe end of the body; the golf club further comprises a second weightthat interlocks with the second end portion of the body; and the bodycomprises a material comprising a density less than that of the weightand the second weight.